Resin-sealing semiconductor package and method and device for manufacturing the same

ABSTRACT

The present invention is characterized in that a powdery or granular resin composition stirred and melted in an agitating pot having a heater, the agitated and melted resin composition is taken out and formed in the form of a package under pressure, and the formed resin composition is fitted to a compression plunger inside a cavity of a lower molding unit, a semiconductor package is molded by sealing under pressurizing with the compression plunger. Even when the wires are thinned and arranged at a higher density, the above producing method can provide such method and apparatus for producing the resin-sealed type semiconductor packages that produce less flowing of the wires.

TECHNICAL FIELD

The present invention relates to resin-sealed type semiconductorpackages and production method and apparatus therefor. For example, theinvention is favorably used as a method for producing resin-sealed typesemiconductor packages by sealing transistors, semiconductor chips suchas IC and LSI, electronic parts, etc. with resin compositions.

PRIOR ART

Heretofore, a transfer molding has been widely used as a known methodsuitable for sealing transistors, semiconductor chips such as IC andLSI, other electronic parts, etc. with epoxy resin sealing materialssuitably from the standpoint of low costs as well as high reliabilityand productivity. This is shown in FIG. 15.

According to this transfer molding, the following is a common method.That is, the epoxy resin sealing material is preliminarily formed as atablet, and the tablet 72 is placed in a pot 62 of a molding die 61, andpressed with a feeding plunger while being melted under heating.Thereby, the melt is fed into a molding cavity 63 via various flow pathsincluding a transfer pot, a runner 64 and a gate 65. The epoxy resinsealing material is formed and cured and simultaneously a semiconductorpackage is molded by sealing a lead frame 63 a to which semiconductorchips or electronic parts are attached.

However, this method is based on the assumption that the epoxy resinsealing material is preliminarily formed in the form of the tablet, andtherefore additional forming step is necessary. Since such tabletsdiffer depending upon shapes and sizes of products to be formed bymolding. Thus, many tablet machines and molding dies are required forsuch tables. Further, there are problems that tablets are broken duringtransferring and fine powder attached to surfaces of the tablets scatteron surfaces of molding dies and deteriorate quality of the products.

Furthermore, according to the transfer molding method, most of the resinremaining in the transfer pot, the runner and the gate is disposed of asan unnecessary cured resin, so that there is a limit in increasing aresin efficiency as a ratio of the used sealing resin to the total one.Moreover, since tablets need to be stored in different sizes dependingupon those of products, it is troublesome to effect inventory controlfor the tablets. Thus, there is a problem from the standpoint ofeffective utilization of resources as well as cost performance.

To the contrary, a compression molding method is proposed in which aresin-sealing molding die composed of upper and lower split molding diesis maintained at a given high temperature, a thermosetting resin isapplied inside the molding die and melted there, a lead frame or a TABtape having semiconductor chips mounted thereon is fixed in the moldingdie, and a package is formed by applying pressure upon the molding die.See Patent Document 1, for example.

Another compression molding method is proposed in which a sealing resinsheet composed of a non-cured resin is arranged at least on anactivating face of semiconductor chips connected to an outsidelead-constructing body via bonding wires, and a package is formed bypressing the sealing resin sheet upon the semiconductor chips. SeePatent Document 2, for example.

Further, a further compression molding method is proposed in which alead frame or a tape frame having semiconductor chips mounted thereon isinserted into a molding die, a sheet-shaped resin is fed directly into acavity, and a package is formed under pressure in the state that bottomfaces of upper and lower cavities are acting as forming plungers. SeePatent Document 3, for example.

A still further compression molding method is proposed in whichsemiconductor chips provided on a carrier are placed together with athin plate-shaped resin chip in a molding die composed of upper andlower molding units one of which is opened and closed relative to theother, and a package is formed by pressing the resin chip upon thesemiconductor chips. See Patent Document 4, for example.

These four Patent Documents 1 to 4 propose that the compression moldingmethods can be utilized as semiconductor-sealed body-producing method tocope with requirements that the sealing step can be automated in aninline system and suited for enlarged scales, reduced thicknesses, andhigh integration of packages with high reliability.

However, since the applied resin, the resin sheet or the resin chip ispreliminarily heated on the molding die at a high temperature of around170° C. for a given time period and then subjected to compressionmolding, there exists a problem that metal wires are deformed due toincrease in viscosity with progress in curing of the sealing resin.Further, as to the transfer molding, there are problems that apparatusesfor producing the tablets, the resin sheets or the resin chips areneeded and resulting tablets, resin sheets or resin chips are requiredto be stored.

Patent Document 1: JP-A 8-111465 (page 2 to 5)

Patent Document 2: JP-A 6-275767 (pages 2 to 9)

Patent Document 3: JP-A 8-330342 (Pages 2 to 6)

Patent Document 4: JP-A 9-187831 (pages 2 to 10)

DISCLOSURE OF THE INVENTION

The present invention has been made to solve the problems that whensemiconductor packages become larger, more thinned and more highlyintegrated, the wires are more likely to be flown and high reliabilityis difficult to be attained. The invention is aimed at the provision ofa method and an apparatus for producing a resin-sealed typesemiconductor package in which the wires are difficult to be flown evenwhen semiconductor packages become larger, more thinned and more highlyintegrated.

Further, the present invention is aimed at the provision of a method andan apparatus for producing a resin-sealed type semiconductor package,while enabling increased productivity and effective utilization of theresin with a reduced waste amount of the resin by omitting theconventional resin tablets and effecting a forming step in an inlineprocess.

The present invention is directed to the following methods <1> to <7>:

<1> a resin-sealed type semiconductor package-producing methodcomprising (1) feeding a powdery or granular resin composition into aweighing pot and weighing the resin composition, (2) feeding the resincomposition from the weighing pot to an agitating pot having a heater,(3) agitating and melting the resin composition in the agitating pot,(4) taking out the agitated and melted resin composition and forming itin the form of a package under pressure, (5) fitting a lead frame or atape substrate on which semiconductor chips or electronic parts areattached to a cavity of an upper molding die unit of a molding diehaving a heater, (6) fitting the formed resin composition to acompression plunger inside a cavity of a lower molding unit, (7) afterclamping the molding die, obtaining an integrally molded body by sealingthe semiconductor chips or electronic parts and the lead frame or tapesubstrate through pressing the resin composition with the compressionplunger and molding and curing the resin composition, and (8) taking outthe integrally molded semiconductor package from the molding die.

<2> In the above step (3) of <1>, temperature of the agitating pothaving the heater is in a range of 80° C. to 120° C. when the resincomposition is melted under agitating.

<3> In the above step (3) of <1> or <2>, the time for melting the resincomposition under agitating is in a range of 10 to 50 seconds.

<4> In the above step (4) of any one of <1> to <3>, the temperature ofthe molding die is in a range of 50° to 100° C. with a pressing pressure(forming pressure) of 9.8 KN to 39.2 KN when the resin composition ispressed and formed.

<5> In the above step (4) of any one of <1> to <4>, the formed resincomposition has a shape which is substantially similar to an outer shapeof a molding bottom face of the lower cavity and smaller than this outershape of the cavity of the lower molding unit by a range of 0.1 to 0.5mm.

<6> In the step (4) of any one of <1> to <4>, an area of one face of theformed composition is not less than 90% of that of a molding bottom faceof the cavity of the lower molding unit.

<7> The resin-sealed type semiconductor package obtained by any one of<1> to <6> is diced within a frames defined by an uneven line formed ata bottom face thereof along an outer shape of the end face of thecompression plunger.

<8> A resin composition-sealed type semiconductor package-producingapparatus comprises (1) a weighing unit for feeding a powdery orgranular resin composition into a weighing pot and weighing it, (2) aresin feeder for feeding the resin composition from the weighing potinto an agitating pot having a heater, (3) an agitating/melting unit foragitating and melting the resin composition in the agitating pot byrotating an agitating rod projecting from a tip of an agitating plunger,(4) a forming unit for taking out the agitated and melted resincomposition and forming it in the form of a package under pressure, (5)a device for attaching an object to be sealed, said device being adaptedfor attaching a lead frame or a tape substrate on which semiconductorchips or electronic parts are attached to a cavity of an upper moldingunit of a molding die having a heater, (6) a sealing resin-fittingdevice for fitting the formed resin composition to a compression plungerinside a cavity of a lower molding unit, (7) a sealing device forobtaining an integrally molded body, after clamping the molding die, bysealing the semiconductor chips or electronic parts and the lead frameor tape substrate through pressing the resin composition with thecompression plunger and molding and curing the resin composition, and(8) a takeout device for taking out the resulting semiconductor packagefrom the molding die.

<9> A resin-sealed type semiconductor package is produced by any of theproducing methods <1> to <7> or the apparatus in <8>.

The producing method and apparatus of the present invention are suitablefor producing the resin-sealed type semiconductor package which becomeslarge, thinned and highly integrated, since the wires are difficult tobe flown even in case that the wires are thinned and highly dense.

Further, according to the producing method and apparatus of the presentinvention, since the transfer pot, the runner and the gate are omitted,the use amount of the resin and the amount of the waste resin can be notonly reduced, but also the molding die can be made compact. Further,since the resin fed into the molding die is melted under agitating, theresin needs not be preliminarily heated inside the molding die, so thatthe curing time can be shortened and the productivity can he enhanced.

Furthermore, according to the producing method and apparatus of thepresent invention, the sealing resin to be fed in the agitating step maybe powdery or granular. Since the resin needs not be any of a tablet, aresin sheet or resin chips, a forming step is unnecessary forpreliminarily treating the sealing resin. Further, it is possible toobtain practical effects that a troublesome inventory control isunnecessary unlike the case of using the resin tables, the resin sheetsor the resin chips.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plane view showing a principal portion of a lower moldingunit of a sealing/molding apparatus according to an embodiment of thepresent invention.

FIG. 2 is a sectional view of the lower molding unit of FIG. 1 cut alongan X-X line.

FIG. 3 is a schematic side view for illustrating the sealing/moldingapparatus.

FIG. 4 is a view of FIG. 3 as viewed in an arrow direction of A.

FIG. 5 is a view of FIG. 3 as viewed in an arrow direction of B.

FIG. 6 is a front view showing a principal portion in forming with thesealing/molding apparatus according to the embodiment of the presentinvention.

FIG. 7 is a schematic view for illustrating the state a formed resin FRas one step in forming with the sealing/molding apparatus according tothe embodiment of the present invention.

FIG. 8 is a schematic view for illustrating a fitting step of the formedresin as one step in sealing with the sealing/molding apparatusaccording to the embodiment of the present invention.

FIG. 9 is a schematic view for illustrating a compression forming stepas one step in sealing with the sealing/molding apparatus according tothe embodiment of the present invention.

FIG. 10 is a schematic plane view of illustrating a state that the lowermolding unit 1 is opened to illustrate the shape of the molded productobtained in FIG. 9.

FIG. 11 is a schematic view of illustrating a takeout step as one stepin sealing with the sealing/molding apparatus according the embodimentof the present invention.

FIG. 12 is a view for illustrating the shape of a formed resin in thesealing/molding apparatus according to the embodiment of the presentinvention for comparison with the outer shape of the comparison formedresin FR.

FIG. 13 is another schematic view for illustrating the outer shape of aformed resin in the sealing/molding apparatus according to theembodiment of the present invention for comparison with the outer shapeof the comparison formed resin FR.

FIG. 14 is a further schematic view for illustrating the shape of aformed resin in the sealing/molding apparatus according to theembodiment of the present invention for comparison with the outer shapeof the comparison formed resin FR.

FIG. 15 is a schematic sectional view for illustrating a sealing stepwith the conventional sealing/molding apparatus.

BEST MODE FOR CARRYING OUT THE INVENTION

In the following, specific embodiments for carrying out the presentinvention will be explained with reference to the drawings. Illustrationwill be made, while same reference numerals are given to sites andmembers which are identical with or equivalent to those in theconventional apparatus illustrated.

Regarding the present invention, an invention “apparatus and method forfeeding a resin material” as described in JP-A 2001-341155 may be usedas a preferred embodiment of the forming method and apparatus in whichwires are more difficult to be flown as compared with the conventionaltransfer molding method and the conventional compression molding methodin which the resin sheet is fed.

A resin material feeder shown in this unexamined patent publicationcomprises a weighing unit for feeding the resin into a weighing pot andweighing it, a transfer unit for transferring the resin material fromthe weighing unit to an agitating pot having a heater, anagitating/melting unit for agitating and melting the resin material inthe agitating pot by rotating an agitating rod projecting from a tip ofan agitating plunger, and a feeding unit for extruding the agitated andmelted resin material toward a molding pot of a molding die.

As shown in FIGS. 1 and 2, the present invention uses a sealingapparatus (compression molding apparatus) in which a tip face 3 a of aplunger is taken as a forming face in the present invention instead ofthe above pot of the molding die and a compression molding is utilizedwith a resin-receiving section 7 provided above the tip face 3 a.

Further, according to the present invention, an inloader is provided,which feeds the resin composition heated and agitated in the feedingunit to the resin-receiving section 7 after the resin composition ispressed and formed in a package form with a forming unit assembled intothe producing apparatus as mentioned above. After the thus formed resincomposition is led into the resin-receiving section 7 from the inloader,the sealing device (compression molding apparatus) is clamped and objectto be sealed is sealed with the resin composition during being heatedand cured by raising the compression plunger 3 to a given position. Suchresin-sealed type semiconductor package-producing method and apparatuscan afford an effect that the wires are more difficult to be flown ascompared with the conventional transfer molding method and theconventional compression molding method in which the resin sheet or theresin chips is fed.

In the following, the resin-sealed type semiconductor package-producingmethod and apparatus will be described in detail, which can perform thecompression molding by feeding the resin composition formed in thepackage shape after being agitated into the sealing apparatus(compression molding apparatus) in connection with the above resinmaterial-feeding apparatus and method.

As shown in FIG. 3 to FIG. 6, the resin-sealed type semiconductorpackage-producing apparatus according to the present invention comprisesa sealing/molding apparatus 20 which is equipped with a feeder for apowdery or granular resin composition R (hereinafter referred to as“powdery resin R”) and is roughly composed of a weighing unit (FIG. 4),an agitating unit (FIG. 5) and a forming unit (FIG. 6).

The weighing unit 21 leads the powdery resin R stored in a hopper 22into a weighing tube 24 a under rotation of a screw 24, and the powderyresin is measured by rotating the screw 24 inside the weighing tube 24a. Thereby, the power is successively charged into plural weighing pots25 arranged.

The agitating unit 31 shown in FIG. 5 transfers the measured powderyresin R between the weighing pot 25 and an agitating pot 32 having aheater. Into the agitating pot 32 is fitted a plunger 37 havingagitating rods 37 a projecting from its tip, and the resin is agitatedand melted under rotation of the plunger 37.

The forming unit 83 shown in FIG. 6 takes out the agitated and meltedresin composition MR (hereinafter referred to as “melted resin MR”) andfeeds it into a forming receptacle 80, and the resin composition MR isformed in a package shape by pressing it with an oil hydraulic press 82via a plunger 81.

The outer shape of a sealed portion of the resin-sealed typesemiconductor is restricted to the shape of a side face 4 b of acavity-molding section (molding section) 4. In the present invention,the shape of the inner peripheral face of the forming receptacle 80 isdesigned substantially identical with the outer shape of the sealedportion of the resin-sealed type semiconductor package. “Substantiallyidentical with” in shape means that the outer shape of the formed resincomposition (hereinafter referred to as “formed resin FR”) issubstantially identical with that of the sealed portion of theresin-sealed type semiconductor package. In the present invention, theflowing of the wires is suppressed by reducing the flowing of the resinin a plane direction as much as possible during the sealing step throughmaking the outer shape of the formed resin FR substantially identicalwith the sealed shape of the sealed portion of the resin-sealed typesemiconductor package.

A transfer unit 85 shown in FIG. 8 transfers the resin composition FRformed by the inloader assembled into the producing apparatus toward amolding die 61, and feeds the formed resin FR into a resin-receivingsection 7. A lower molding cavity block 1 is exchangeably set in a lowermolding unit 61B. When the formed resin FR is carried to above theresin-receiving section 7 of the cavity block 1 of the lower moldingunit by the transfer unit 85, adsorption of a adsorbing pads 86 fittedto the transfer unit 85 are stopped to feed the shaped resin FR to theresin-receiving section 7.

FIG. 1 is a plane view for illustrating the lower molding cavity block1, and FIG. 2 is a sectional view of FIG. 1 cut along an X-X line. Inthese figures, a cavity forming section (molding section) 4 is providedas a product-molding section) in a central portion of the lower moldingcavity block 1. A bottom face 4 a of the molding section 4 is cut in analmost central portion as a through-hole section 5 in the form of arectangular column, and a compression plunger 3 is vertically movablyfitted in the through-hole section 5.

A tip face 3 a of the compression plunger 3 is designed to have a shapesubstantially similar to the outer shape of a surface Pa of the sealedportion of the resin-sealed type semiconductor package as a product.Herein, “substantially similar shape” includes a similar shape as wellas an improved design in which a curvature (rounded portion) is providedat a corner portion, for example. In this case, when the tip face 3 a ofthe compression plunger 3 is at the same level with the bottom face 4 a,the lower cavity portion is equal to the molding section 4.

The compression plunger 3 is movable to-and-fro by a reciprocalmechanism 6. Although this reciprocal mechanism 6 is not particularlylimited, a mechanism of which forward and rearward moving amounts can beaccurately controlled with a servo motor, an encoder or the like ispreferred.

The reciprocal mechanism 6 for the compression molding means that thereciprocating mechanism 6 can maintain force necessary for compressionmolding. When pressure needs to be controlled, a mechanism forcontrolling the molding pressure via a pressure detector such as apressure sensor has only to be provided at any location. Such pressurecontrolling mechanism is known, and a pressure detector such as the loadcell may be interposed between the compression plunger 3 and thereciprocal mechanism 6 to maintain the necessary pressure based on thepressure detected by the pressure detector.

When the position of the tip face 3 a of the compression plunger 3 isretracted from the position (hereinafter referred to as “moldingdie-aligning position”) of the lower face 4 a of the molding section 4,the resin-receiving section 7 for receiving the resin is formed abovethis tip face 3 a. For example, in FIG. 2, the compression plunger 3 isretracted to form the resin-receiving section 7 above the tip face 3 aso that the formed resin FR after being agitated and melted may be fedtherein.

(1) Weighing Step

The weighing step is a step by which a powdery resin R fed into thehopper 22 is fed into the weighing pot 25 by the weighing unit 21.

As shown in FIG. 4, the powdery resin R fed into the hopper 22 through aresin composition feeding port 22 a is loosened inside the hopper 22with loosing pins 22 c hanged from a rotary disc 22 b similarly rotatingaround a screw 24 rotated by a weighing motor 23 without forming bridge,so that the powder may be easily bit around the screw 24, andsufficiently and quantitatively fed. When the screw 24 is rotated insidethe weighing tube 24 a at given rpm, a given amount of the powdery resinR is measured, and fed to the weighing pot 25 of the pot 25A from theweighing section 21A.

The feeding motor 27 is operated to move the weighing section 21A withinthe frame body 29 along above the upper end faces of the weighing pots,so that the powdery resin R is charged into all the weighing pots 25(See FIGS. 3 and 4).

In the present invention, the method and the apparatus for weighing thepowdery resin R are not particularly limited to those using the aboveweighing unit 21, and any method and apparatus may be used so long asthe powdery resin R can be measured into the weighing pots 25 with givenaccuracy. For example, a quantitative feeder such as a weighing feederor a spiral feeder commonly employed can be used.

(2) Resin Transfer Step

The resin transfer step is a step in which the powdery resin R is fedinto the agitating pot having a heater from the weighing pot 25.

In this step, as shown in FIGS. 3 and 5, when the powdery resin R ischarged into each of the weighing pots 25 in the above weighing step,the pot-moving cylinder 28 is operated to move the pot section 25A, andthe pot-moving cylinder 33 is operated to accept the agitating pot 32.Then, an on/off cylinder 26 is operated under the weighing pot 25 toopen a shutter plate 26 a, so that the measured powdery resin R is ledfrom the weighing pot 25 to the agitating pot 32. Successively, thepot-moving motor 33 is moved to an original position, and the agitatingpot 32 is located under the plunger 37.

(3) Agitating/Melting Step

The agitating/melting step is a step in which the powdery resin R ismelted in the agitating pot by rotating the agitating rods projectedfrom the tip of the agitating plunger and the melted resin MR is takenout.

In this step, a cylinder 36 a for the agitating rod is operated toproject the agitating rods 37 a from the tip of the plunger 37, andsuccessively the agitating motor 38 to which a gear 38 a is fitted is sooperated as shown in FIG. 5 that the plunger 37 is rotated to stir andmelt the powdery resin R inside the agitating pot 32 having the heater.

While the agitating unit 31 is agitating the resin, the moving motor 52fixed to a rail 56 of the moving unit 51 via a stay 58 is rapidlyoperated to drive a timing belt 54 so that the agitating unit may bemoved, on the rails 56 and 57 to a position to which a limit switch 56 aacts.

After agitating and melting the resin, the agitating rod cylinder 36 ais operated to raise a movable plate 44 and put the agitating rods 37 ainto the cylinder 37.

Then, the vertically moving motor 45 is operated to rotate a ball screw42 via a pulley 45 a axially attached to the motor and a belt 45, andeach plunger 37 fitted to a descending ball screw nut 43 via a lowerconnection plate 36 is lowered at one stroke to take out the moltenresin MR agitated and melted in the agitating pot 32.

In the agitating/melting step of the present invention, the temperatureof the agitating pot having the heater is preferably in a range of 80°C. to 120° C. Although depending upon the kind and the characteristicsof the sealing resin used, the temperature is preferably in a range of90° C. to 110° C. If the temperature of the agitating pot is not morethan 80° C., there may be problems that the powdery or granular resin isnot fully melted and non-melted resin precipitates to disable a givenweight of the resin to be fed, and the curing time cannot be shorteneddue to the lower resin temperature. Accordingly, there occurs a problemthat the resulting sealed product contains much voids due to thesedefects. On the other hand, if the temperature is not less than 120° C.,it may be that the curing is promoted due to too high temperature toaccelerate the gelation of the resin. This causes increased viscosity,lowered flowability and deteriorated thermal stability. As a result, thesealed product suffers from insufficient resin-charging, numerous voids,quality problems such as wire deformation and breakage in the sealedmolded product as well as damaged continuous moldability.

Further, the agitating/melting time is preferably in a range of 10 to 50seconds in the agitating/melting step of the present invention. Althoughassociated with the temperature of the agitating pot, theagitating/melting time is preferably in a range of 20 to 40 seconds.

If the agitating/melting time is shorter than 10 second, the powderyresin R is not fully melted, so that the rotary torque of the agitatingrod needs to be increased. Thus, the capacity of the agitating motorneeds to be increased, which prevents the entire apparatus from beingmade compact. Further, the same problems as in the case of the lower pottemperature occurs with respect to the productivity and quality. On theother hand, if the agitating/melting time is longer than 50 seconds, itmay be that the thermal stability of the molten resin is deterioratedand curing is promoted to accelerate the gelation, although theagitated/melted state is good and the curing time can be shortened.Consequently, the sealed product suffers from insufficientresin-charging, numerous voids, quality problems such as wiredeformation and breakage in the sealed molded product as well as damagedcontinuous moldability.

(4) Forming Step

The forming step is a step in which the molten resin MR is taken out andformed in a package shape under pressure, thereby obtain a formed resin.

In this step, the molten resin MR agitated and melted in the agitatingpot 32 is taken out, and as shown in FIGS. 6 and 7, is fed to thereceiving table 84 with the forming receptacle 81 and the heater, andformed into a semiconductor package under pressure by the plunger 81connected to the oil hydraulic press 82. Thereby, the formed resin FR isobtained.

In the forming step of the present invention, the temperature of thereceiving table having the heater is preferably in a range of 50° C. to100° C. when the resin is formed under pressure. Although depending uponthe kind and the characteristics of the sealing resin used, thetemperature is preferably in a range of 60° C. to 90° C. If theconventional tablet or powdery or granular resin composition is used,such is difficult to be softened and formed in this temperature range.However, since the molten resin composition MR is already present in theagitating pot 32 by agitating and melting, the resin composition can beformed. If the forming temperature is less than this range, the formedresin FR can not be obtained in the package shape due to occurrence ofthickness spots and density spots in the formed resin FR, althoughdepending upon the pressure mentioned later. As a result, the resincannot be uniformly compressed during compression molding mentionedlater, so that the wires are partially flown or many voids are formed.On the other hand, if the forming temperature is higher than the abovetemperature range, it may be that burrs are formed in gaps among theplunger 81, the forming receptacle 80 and the receiving table 84 and agiven weight of the formed resin FR may not be obtained. As the case maybe, the resin vigorously attaches to the plunger 81 and the receivingtable 84, so that it is difficult to clean them, resulting in damagingthe continuous moldability.

In the forming step of the present invention, the pressurizing force(forming pressure) is preferably in a range of 9.8 KN to 39.2 KN.Although depending upon the kind and the characteristics of the sealingresin used, the forming pressure is preferably 19.6 KN to 29.4 KN. Ifthe forming pressure is in such a range, the ordinary powdery orgranular resin can hardly be formed. According to the present invention,since the molten resin MR already agitated and melted in the agitatingpot 32 is received directly in the forming step, it can be formed undersuch a low forming pressure.

If the forming pressure is lower than the lower limit, it may becomedifficult to form the resin in a package shape, and a large non-chargedstate may occur particularly in a corner portion. Although the resin canbe formed in the package shape by raising the forming temperature, theraised forming temperature may generate the above-mentioned problems. Onthe other hand, if the forming pressure exceeds the upper limit, thepressurizing force with the oil hydraulic press needs be raised, whichhinders compacting of the apparatus.

The package shape in the present invention means the sealed shape of thesealed portion of the resin-sealed type semiconductor package restrainedby the shape of the cavity-forming section (molding section) 4. In thepresent invention, the outer shape of the formed resin FR is preferablysubstantially identical with the sealed shape of the sealed portion ofthe resin-sealed type semiconductor package of products.

The formed resin FR can be fitted into the resin-receiving section 7. Inpractice, considering the above fitting the FR to the resin-receivingsection, the outer shape of the formed resin FR needs to be designedslightly smaller than that of the tip face 3 a of the forming plunger.Accordingly, “substantially identical with the outer shape of thepackage” means, for example, that the outer shape of the formed resin FRis smaller than that of the sealed portion of the resin-sealed typesemiconductor package by a range of 0.1 to 0.5 mm, provided that bothare designed similar to each other or that the area of one face of theformed resin FR is not less than 90% of that of the surface 3 a′ of thesealed portion.

(5) Frame-Fitting Step

The frame-fitting step is a step in which a object to be sealed, such asa lead frame or tape substrate F on which semiconductor chips H (orelectronic parts) are mounted is fitted in an upper molding cavity ofthe molding die having the heater.

In this step, as shown in FIG. 8, the tape substrate F (or the leadframe) as the aimed object is fitted onto a surface of the upper moldingcavity block 2 attached to the upper molding unit 61A via an inloader(not shown) for integration, arraying and discharging of the tapesubstrate (or the lead frame 63 a) on which the semiconductor chips H(or the electronic parts) are attached. At that time, a holder for thetape substrate F (or the lead frame 63 a) is not particularly limited,and vacuum suction or mechanical set not shown may be utilized, forexample.

(6) Formed Resin-Fitting Step

The formed resin-fitting step is a step in which the formed resin FR isfitted to the compression plunger inside the lower molding cavity.

As shown in FIG. 8, according to this step, the transfer unit 85 movesthe formed resin FR toward the molding die 61, and the absorption pads86 attached to the transfer unit 85 are actuated to fit the formed resinFR to the resin-receiving section 7 at a point of time when the formedresin FR is located in the resin-receiving section of the lower moldingcavity block 1 exchangeably set in the lower molding unit 61B.

(7) Compression Set:

The compression step is a step in which the semiconductor chips or theelectronic parts and the tape substrate or the lead frame are integratedby sealingly molding by molding and curing the formed resin FR throughpressurizing with the compression plunger after clamping the moldingdie.

According to this step, as shown in FIG. 9, after the molding die isclosed by descending or ascending at least one of the upper moldingcavity block 2 and the lower molding cavity block 1 with a moldingdie-clamping mechanism, the reciprocal mechanism is driven to raise(advance) the tip face 3 a of the molding plunger 3 to a moldingdie-aligning position (molding face) and perform the compressionmolding.

According to the compression molding of the present invention, since theformed resin FR fed to the resin-receiving section 7 is appropriatelypreheated immediately after being formed by pressurizing under heating,the formed resin can obtain at once flowing ability optimum for thesealing immediately after being fed into the resin-receiving section 7.

In this embodiment, as shown in FIGS. 8 to 11, CSP in which thesemiconductor chip H is held at one face of the tape substrate F andmetallic wires W are connected thereto is used. Since sealing iseffected from under the semiconductor chip to be sealed, the flowingdistance of the molten resin flowing in the sealing member containingthe metallic wires W can be shortened. In addition, since the formedresin FR is formed in the package shape, the flowing rate at which theformed resin FR is melted and flown can be retarded. Consequently, theflown degree of the wires can be reduced even in case of the metallicwires W at a finer pitch.

According to such a compression step, the molded face 3′a of theresulting semiconductor package (product) P (See FIG. 11) formed by thecompression plunger 3 is formed with that mark 3 ab′ meeting the shapeof the tip face 3 a of the compression plunger 3 which goes up and downdepending upon variations in weight of the formed resin FR.

Here, according to this embodiment, as shown in FIGS. 8 and 10, sincethe outer shape of the tip face 3 a of the compression plunger 3 isdesigned slightly smaller than that of the bottom face 4 a of the cavity4 by a range of 0.1 mm to 0.5 mm, the uneven mark 3 ab′ does notsubstantially influence the performance of the product if the weightvariations of the formed resin FR charged are appropriately controlledwithin a range of around ±0.1 g.

Further, in the case of packages such as package molding (usually calledMAP) including CSP and BGA, since the molded product is diced intoindividual ones within frames of the uneven marks 3 ab′ after beingremoved from the molding die, no such an uneven mark 3 ab′ remains, sothat no influence is substantially caused upon the shape and theperformance of the product.

(8) Takeout Step

The takeout step is a step in which the semiconductor package as theintegrally molded product is taken out from the molding die.

In this step, the upper and lower molding units 61 are opened by themolding die-clamping mechanism after the resin is cured, and the productis taken out as the sealingly molded product P by any means (See FIG.11). Although the absorbing unit such as the absorbing pads is used totake out the product P, a thrust pin or thrust plate may be used fortaking out it.

As shown in FIG. 11, the product P may be taken out by lowering(retracting) the compression plunger 3 with the reciprocating mechanism6. By so doing, the product P can be taken out without a takeout devicesuch as a projecting pin for taking out the product in the lower moldingcavity block.

The resulting product P is sent to a succeeding step with an unloader orthe like after being timely discharged and collected. Burrs, dirt andthe like on split faces of the molding die are cleaned with a cleaner toprepare a next molding cycle.

According to the method and apparatus for producing the resin-sealedtype semiconductor package in the present invention as explained above,the semiconductor package in which the wires are unlikely to flow evenif the metallic wires are thinned at a higher density can be obtained.

Further, the resin tablet used in the multi-transfer molding can be madeunnecessary, and enhanced productivity and effective utilization of theresin can be attained, while decreasing the amount of the resin waste.The gate-broken molded product can be obtained without passing aso-called gate break step by which the unnecessary resin remaining inthe runner etc. is separated from the molded product.

Although effects of the present invention will be explained based on thefollowing examples, the invention is not limited thereto.

EXAMPLE Example 1

A sealingly molded product was produced by using a agitating pot at onesite in the sealingly molding method and apparatus shown in FIGS. 1 to11. As a sealing resin, an epoxy resin molding material: SUMIKON“EME-7730” (Commercial name) manufactured by Sumitomo Bakelite Co., Ltd.was used.

Molding was actually effected under the molding condition that thetemperature of the agitating pot 32 was 100° C., the agitating time was30 seconds, the temperature of the forming receptacle 80 and the formingreceiving table 84 was 80° C., the forming pressure was 24.5 KN, theinjection pressure of the compression plunger 3 was 9 MPa, the injectiontime was 12 seconds, the curing time was 100 seconds, and thetemperature of the molding die was at 175° C.

A molding die was used for molding 12 chips at one time in a package of12 chips/1 frame. A tape substrate in which metallic wires were bondedto stacked chips consisting first-stage chips of 8 mm×6 mm andsecond-stage chips of 3.5 mm×3.5 mm with a charging thickness of 200 μmwas set and molded in the molding die. With respect to the sealinglymolded product, non-charged state, outer voids, inner voids, wireflowing and resin waste rate were evaluated.

Comparative Example 1

As comparison, multi-transfer molding, which was carried out under thesame molding condition except that a minitablet having a diameter of 14mm was used in a molding apparatus as shown in FIG. 15, and thepreheating time in the molding die was set at 4 seconds, was compared.

Results were shown together in Table 1. TABLE 1 Example 1 ComparativeExample 1 Invention molding Multi-transfer Molding method method moldingmethod Non-charged state 0/3 0/3 Outer voids 0/3 0/3 Inner voids 0/3 0/3Wire sweeping 2.6% 16.6% Resin waste rate 3.7% 75.7%(Measuring Methods)1. Non-Charged State (Short Shot)

Presence or absence of the non-charged state (Short shot) was visuallyobserved at surface.

2. Outer Voids

Presence or absence of the outer voids greater than 0.5 mm in diameterat surface was observed by a binocular microscope (×10).

3. Inner Voids

Presence or absence of the inner voids greater than 0.3 mm in diameterwas observed by irradiating soft X-rays upon the molded product.

With respect to numbers shown in Table 1, the denominator gives thenumber of packages observed which were each formed by molding 12-chippackages together, and the numerator gives the number of packagessuffering abnormality.

4. Wire Sweeping (Wire Deformation)

A deformed amount of bonding wire (high strength metallic wire, 25 μm indiameter and 3.4 mm length) was measured by irradiating soft X-rays uponthe molded product. The wire flowing was shown by a ratio (%) of amaximum deformed amount (%) of the wire to a distance in bonding betweenan end face of the semiconductor chip and an end of a tape lead. InTable 1, the figure shows the average value of maximum deformed amountsof 36 chips (evaluated three packages each containing 12 chips/oneframe).

5. Resin Waste Rate

The resin waste rate was shown by a ratio (%) of a total resin amountincluded in the transfer pot, runner, gate, etc. to a necessary resinamount in the package of 12 chips/one frame.

Example 2

Example 2 is an example to confirm influences upon performance of themolded product when the shape of the formed resin FR was changed.

As a molding die, a chip size package CPS for molding 12 chip/one frame(MAP) at one stroke was used, and a surface of a sealed portion was38.70×38.35 mm. A chip size of each semiconductor device H is about 5mm, and a bonding wire W is a high strength metallic wire of 25 μmdiameter and 3.30 mm length.

In order to vary the shape of the formed resin FR, the size and theshape of the forming receptacle 80 were changed as shown in FIGS. 12 to14. The tip face 3 a of the plunger 3 was designed to have such amaximum area as to receive the formed resin FR in the resin-receivingsection 7. By this construction, a contour line 3 ab of the tip end 3 a,which is shown in a chain double-dash line was set greater than theouter contour line (formed outer line) f of the formed resin FR by arange of 0.1+0.1 mm (0.1 mm to 0.2 mm).

In Example 1 illustrated in FIG. 12, a distance w between the outercontour line 4 ab′ and the formed outer line f of the formed resin FRshown by an alternate long and short chain line was set at about 0.3 mm(plunger size: 37.80×37.45 mm), a radius of curvature of each of fourcorners FRR of the formed resin FR is set at about 2 mm. Thereby, theratio of the area of one surface of the formed resin FR relative to thatof an area surrounded by the outer contour line 4 ab (outer contour line4 ab′ of the product) is about 96.5% (measured).

In Example 2 of FIG. 13, the distance w identically defined is set atabout 0.6 mm (plunger size; 37.7×37.35 mm), a radius of curvature ofeach of four corners FRR of the formed resin FR is set at about 10 mm,and the ratio of the area of one surface of the formed resin FR relativeto that of an area surrounded by the outer contour line 4 ab (outercontour line 4 ab′ of the product) is about 85.2% (measured).

Further, in Example 3 of FIG. 14, a tip face 3 a and a formed resin FRare designed circular, and a minimum width w between the outer contourline 4 ab′ and the formed outer contour line f is set at about 0.3 mm.Thereby, the ratio of the area of one surface of the formed resin FRrelative to that of an area surrounded by the outer contour line 4 ab(outer contour line 4 ab′ of the product) is about 76.5% (measured).

By the above construction, as to the semiconductor package P shown inFIG. 12, the dicing line DL is located inside a frame of the formedouter contour line f of the formed resin FR including four corners DLa.In FIG. 13, the four corners DLa of the dicing line DL expand outwardlyfrom the four corners FRR of the formed FR. In FIG. 14, the formed outercontour line f largely crosses the wires W of the semiconductor packageH.

Molding was actually effected under the molding condition that thetemperature of the agitating pot 32 was 100° C., the agitating time was30 seconds, the temperature of the forming receptacle 80 and the formingreceiving table 84 was 80° C., the forming pressure was 24.5 KN, theinjection pressure of the compression plunger was 9 MPa, the injectiontime was 8 seconds, the curing time was 100 seconds, and the temperatureof the molding die (lower and upper molding units 1 and 2) at 175° C.

By this, the tape substrate having the metallic wires bonded was set inthe molding die, and with respect to the sealed product P, non-chargedstate, outer voids, inner voids, and wire flowing were evaluated.Results are shown in Table 2. TABLE 2 Item Example 1 Example 2 Example 3Width w (mm) 0.3 0.6 0.3 Area ratio 96.5% 85.2%  76.5% Non-charged state0/3 0/3 0/3 Outer voids 0/3 0/3 0/3 Inner voids 0/3 0/3 0/3 Wiresweeping 2.70% 8.50% 10.20%

From the above results, it is understood that the non-charged state, theouter voids, the inner voids, and the wire flowing were reduced when theshape of the formed resin FR is similar to that of the package and theratio of the area of the formed resin to the area of the bottom formingface of the lower molding cavity (area of one surface of the product P)is not less than 90%.

In the above, the examples of the present invention have been detailedbased on the drawings, but specific constructions of the presentinvention are not limited thereto. Any changes in design not departingfrom the gist of the present invention are encompassed by the invention.

As explained before, the resin-sealed type semiconductorpackage-producing method and apparatus can be effected in the inlinemanner. Even if the process for producing the resin-sealed typesemiconductor package is entirely automated through the inline system,the wires are unlikely to be flown and the resin waste amount can bereduced. Thus, the present invention ensures high reliability even ifthe semiconductor becomes larger, thinned and highly integrated. Inaddition, the present invention is expected to be widely developed asthe method and apparatus for the production of the resin-sealed typesemiconductor packages, which are also fit to the production of otherkinds of a small number of products.

1. A resin-sealed type semiconductor package-producing method comprisingfeeding a powdery or granular resin composition into a weighing pot andweighing the resin composition, feeding the resin composition from theweighing pot to an agitating pot having a heater, agitating and meltingthe resin composition in the agitating pot, taking out the agitated andmelted resin composition and forming it in the form of a package underpressure, fitting a lead frame or a tape substrate on whichsemiconductor chips or electronic parts are attached to a cavity of anupper molding die unit of a molding die having a heater, fitting theformed resin composition to a compression plunger inside a cavity of alower molding unit, after clamping the molding die, obtaining anintegrally molded body by sealing the semiconductor chips or electronicparts and the lead frame or tape substrate through pressing the resincomposition with the compression plunger and molding and curing theresin composition, and taking out the integrally molded semiconductorpackage from the molding die.
 2. The resin-sealed type semiconductorpackage-producing method set forth in claim 1, wherein in the abovestep, a temperature of the agitating pot having the heater is in a rangeof 80° C. to 120° C. when the resin composition is melted underagitating.
 3. The resin-sealed type semiconductor package-producingmethod set forth in claim 1, wherein in said step, the time for meltingthe resin composition under agitating is in a range of 10 to 50 seconds.4. The resin-sealed type semiconductor package-producing method setforth in claim 1, wherein in said step, the temperature of the moldingdie is in a range of 50° to 100° C. with a pressing pressure (formingpressure) of 9.8 KN to 39.2 KN when the resin composition is pressed andformed.
 5. The resin-sealed type semiconductor package-producing methodset forth in claim 1, wherein in said step, the formed resin compositionhas a shape which is substantially similar to an outer shape of amolding bottom face of the lower cavity and smaller than this outershape of the cavity of the lower molding unit by a range of 0.1 to 0.5mm.
 6. The resin-sealed type semiconductor package-producing method setforth in claim 1, wherein in said step, an area of one face of theformed composition is not less than 90% of that of a molding bottom faceof the cavity of the lower molding unit.
 7. A resin-sealed typesemiconductor package obtained by claim 1, s diced within a framedefined by an uneven line formed at a bottom face thereof along an outershape of the end of the compression plunger.
 8. A resincomposition-sealed type semiconductor package-producing apparatuscomprises a weighing unit for feeding a powdery or granular resincomposition into a weighing pot and weighing it, a resin feeder forfeeding the resin composition from the weighing pot into an agitatingpot having a heater, an agitating/melting unit for agitating and meltingthe resin composition in the agitating pot by rotating an agitating rodprojecting from a tip of an agitating plunger, a forming unit for takingout the agitated and melted resin composition and forming it in the formof a package under pressure, a device for attaching an object to besealed, said device being adapted for attaching a lead frame or a tapesubstrate on which semiconductor chips or electronic parts are attachedto a cavity of an upper molding unit of a molding die having a heater, asealing resin-fitting device for fitting the formed resin composition toa compression plunger inside a cavity of a lower molding unit, a sealingdevice for obtaining an integrally molded body, after clamping themolding die, by sealing the semiconductor chips or electronic parts andthe lead frame or tape substrate through pressing the resin compositionwith the compression plunger and molding and curing the resincomposition, and a takeout device for taking out the resultingsemiconductor package from the molding die.
 9. A resin-sealed typesemiconductor package is produced by the producing method set forth inclaim
 1. 10. The resin-sealed type semiconductor package-producingmethod set forth in claim 2, wherein in said step, the time for meltingthe resin composition under agitating is in a range of 10 to 50 seconds.11. The resin-sealed type semiconductor package-producing method setforth in claim 2, wherein in said step, the temperature of the moldingdie is in a range of 50° to 100° C. with a pressing pressure (formingpressure) of 9.8 KN to 39.2 KN when the resin composition is pressed andformed.
 12. The resin-sealed type semiconductor package-producing methodset forth in claim 2, wherein in said step, the formed resin compositionhas a shape which is substantially similar to an outer shape of amolding bottom face of the lower cavity and smaller than this outershape of the cavity of the lower molding unit by a range of 0.1 to 0.5mm.
 13. The resin-sealed type semiconductor package-producing method setforth in claim 2, wherein in said step, an area of one face of theformed composition is not less than 90% of that of a molding bottom faceof the cavity of the lower molding unit.
 14. A resin-sealed typesemiconductor package obtained by claim 2, s diced within a framedefined by an uneven line formed at a bottom face thereof along an outershape of the end of the compression plunger.
 15. A resin-sealed typesemiconductor package is produced by the producing method set forth inclaim 2.